How Do Hydroponic Grow Systems Work?

Lettuce responds very well to hydroponic growing methods.

Hydroponic growing systems allow you to produce plants indoors without any soil. Though such systems also work outdoors, they're an effective choice for people who want to have a garden but don't have appropriate outdoor space. They also allow you to minutely control the environmental conditions for flowers and other sensitive kinds of plants, making it possible to grow species that need different temperatures or light availability than what your climate provides. The basic principle behind growing hydroponically is relatively simple, but the system itself can become very complex.

Wick Systems

The simplest kind of hydroponic grow system, wick systems are completely passive. They use a wick to pull a liquid nutrient solution into the plants' growing medium. This medium can be composed of coconut fiber, perlite, vermiculite or a similar material. An air pump can be used to oxygenate the solution, but the system otherwise has no moving parts. This system is the least expensive and complicated but does not work well for large or very thirsty plants.

Water Culture

Water culture systems are considered the simplest kind of active hydroponic setup, with the plants directly exposed to a nutrient solution. They use a floating foam block to hold the plants with their roots suspended in the liquid nutrients. As in a wick system, air stones and pumps may be used to keep oxygen circulating in the solution. Water-loving plants with a fast growth rate, such as lettuce, do well in this kind of system, but it is appropriate for only a few other species.

Ebb and Flow

This kind of hydroponics system is composed of a growing tray and a reservoir filled with nutrient solution. Periodically, a pump submerged in the nutrient liquid floods the grow tray, then drains it again. This allows the plants to receive regular infusions of nutrients without the need for special oxygenation. Because the plants don't stay submerged, they must be grown in a medium such as gravel or rockwool. Plants that need a lot of moisture can be grown in coconut fiber or vermiculite.

Drip Systems

The drip system is among the most versatile and common hydroponic setups. Like ebb-and-flow systems, the nutrient solution is stored in a reservoir, and the plants are grown separately in a soil-less medium. Unlike other hydroponic systems, drip setups dispense nutrients slowly via small nozzles. Any extra solution can either be collected and recirculated or allowed to drain away. Because the drip timer is adjustable, it's possible to grow many different kinds of plants using this technique.

Nutrient Film Technique

This kind of hydroponic system uses a pump to apply nutrient solution to the plants but requires no timer. Instead, the roots of the plants are exposed to a constant flow of liquid nutrients. No growing medium is required for this kind of system. Instead, plants are suspended in individual baskets. While this method is inexpensive, it can be unstable. The lack of growing medium means that a blackout or short circuit can kill plants very quickly.

Aeroponics

This very high-tech method involves suspending plants above special misting nozzles. The roots are then sprayed with a fine layer of nutrient solution every few minutes. Like nutrient film technique systems, aeroponics systems are vulnerable to pump failure and loss of power, but they allow very fine control.